Referring to U.S. Pat. No. 5,003,962 (Choi), a laryngoscope with a double angle blade is shown. This scope was an improvement on prior art, due to the angles that were defined by the blade. This particular blade had a first angle of approximately 20 degrees, and a second angle, farther along the length of the blade, of approximately 30 degrees. The blade itself had no curvature, but rather was comprised of three separate segments, with the length of each segment defined by a bent portion. This blade relied on the angle segments to adequately keep the person's tongue out of the way during examination, rather than rely on any scallops or curved areas on the blade, as prior art blades had done.
Referring now to U.S. Pat. No. 510,516 (Nithack) exemplifies a means to illuminate a patient's throat. This patent, having been issued in 1893, exemplifies some of the prior art regarding this type of instrument. The blade of this instrument had a longitudinal groove which was placed on the upper side of the person's tongue. The blade itself was flat, with the exception of the hollow groove or ribbon.
Referring now to U.S. Pat. No. 330,139 (Meyer), a scope is shown having a similar intended use. The blade of this particular invention defined a curved surface, however the curvature was defined along the length of the blade and not across the width of the blade. The illumination of a person's mouth, along with holding down their tongue, was the chief utility of this invention. Basically, the blade of this invention did nothing more than attempt to hold a portion of the tongue out of the way of a beam of light. The extent to which a person's tongue would be held out of the way was questionable, and did not seem to be the chief focus of this invention.
Referring now to U.S. Pat. No. 5,575,758 (Easterbrook), where the inventor in this patent paid particular attention to improving the blade used with a scope. The blade itself provided a gentle curved slope along its length, and had a spatula portion, and flange portion. This particular invention however, makes no improvements as to actually restricting the edges of a person's tongue from overlapping or protruding over the sides of the blade, such as would be available through the use of a concave surface being presented to a person's tongue.
Referring now to U.S. Pat. No. 5,529,570 (Storz), a prior art spatula or blade is shown. This particular invention provides for an improved light placement, along with providing a curb on the spatula shaped portion, which is intended to restrict movement of a person's tongue. The surface of the spatula blade is curved along the length, but is flat with regard to the area from side to side of said spatula blade. This particular invention lacks the optimal ability to restrict a person's tongue from protruding over the edges of the spatula blade and assisting in restricting the observable illuminated area of the patient.
Referring now to U.S. Pat. No. 4,947,896 (Bartlett), a scope is shown having a plurality of channels running along the length of the blade. In this invention, various tubes are provided with passageways along full length of the blade. Surface 20 presents a partial convex surface against a person's tongue, which actually promotes and encourages the tongue to spill over the sides of the blade and obstruct the viewing area. There is no adequate cavity defined by the blade which would assist in preventing the tongue from flattening out or widening so that it would not come over the edge of the blade.
Referring now to U.S. Pat. No. 4,834,077 (Sun), a disposable sheath is shown, which is usable with the blades described in various patents, and used in the field of medicine. The sheath itself has a design whereby an extreme curvature in a shown from side to side of the sheath, promoting a concave service on one side and a convex service on the other side of said sheath. In this patent, the concave side is not intended to come into contact with the patient's tongue. Rather the convex surface of the sheath, which is fitted over a similarly shaped blade, is the area of contact. This particular curvature does not inhibit the tongue from spreading out and curbing over the sides of the blade. The convex surface actually promotes and encourages the tongue to flatten out.
Referring now to U.S. Pat. No. 5,665,052 (Bullard), recent improvements with respect to laryngoscopes are shown. This particular invention dealt with the problems where tubes that were not properly positioned would not pass between the vocal cords. In the blade portion of this particular scope, the curvature appears to be only along the length of the blade. There is no concave surface presented to the surface of the patient's tongue, other than the curvature along the blade length. This invention appears to have used during surgical procedures, rather than for routine examination, and the blade portion would normally be inserted farther into the oral cavity and throat than would be required in a routine examination.
Prior art has attempted to overcome visual blockage that often accompanies examination using this device. While prior devices have shown a multitude of blade configurations, the prior blades have not adequately discouraged encroachment of the patient's tongue around and over the sides of the blade. The prior art blades have failed to manipulate a patient's tongue in any manner other than longitudinally, and have ignored the problems inherent with a tongue widening or flattening out, thereby allowing the tongue to wrap itself around the sides of the blade itself. This causes significant loss of the area able to be viewed, and those interferes with optimal patient treatment.